This invention relates to a mold apparatus used in a molding machine such as a rotary injection molding machine and a slide-type injection molding machine.
As a conventional single molding machine for molding a multi-color or a multi-material molded product, there is known, for example, a rotary injection molding machine (see, for example, JP-UM-A-7-15318 Publication). This conventional rotary injection molding machine 1 is constructed as shown in FIGS. 1 to 10. A plurality of fixed molds 3A and 3B are mounted on a fixed platen 2, and are disposed at equal intervals around a rotation axis (center) Ca described later. A movable base 4a is rotatably mounted on a movable platen 4. A plurality of movable molds 5A and 5B are mounted on the movable base 4a through a base 6, and are disposed symmetrically with respect to the rotation axis Ca.
For molding a molded product, one movable mold 5A and one fixed mold 3A are clamped or closed together, and a first-stage molded product is molded. Thereafter, the one movable mold 3A is opened (as shown in FIG. 8), and the movable base 4a is rotated about the rotation axis Ca through an angle of 180 degrees, and by doing so, the one movable mold 5A is rotated or angularly moved (as indicated by arrow A in FIG. 9) to a position where it is opposed to the other fixed mold 3B (while the other movable mold 5B is opposed to the one fixed mold 3A. Then, the movable platen 4 is moved in a mold clamping direction to be clamped to the other fixed mold 3B. At this time, the other movable mold 5B is clamped to the one fixed mold 3A.
In such rotary injection molding machine 1, when the movable molds 5A and 5B were rotated, a mold center Pa (see FIG. 10) of each movable mold 5A, 5B was sometimes slightly (about 0.1 to about 0.2 mm) out of alignment with (or was offset from) a mold center Pb of the corresponding fixed mold 3A, 3B, depending on manufacturing accuracies of the molds and an assembling accuracy of the molding machine or the accuracy of mounting, of the movable molds 5A and 5B on the movable base 4a and a mounting accuracy of the fixed molds 3A and 3B. Therefore, in some cases, the fixed molds 3A and 3B and the movable molds 5A and 5B could not be clamped together, or even if this mold clamping operation could be achieved, the molds were damaged, or the mating molds were brought into biting engagement with each other. These problems were encountered also with slide-type injection molding machines.